1. Field of the Invention
The present invention relates to apparatus and methods for application of a targeted minimum flow of NH3 on agricultural fields. More particularly, a boost pump is used to assist in transferring at least a minimum pressure and flow rate of NH3 from storage tank to tool bar when ambient temperature is too cold or delivery systems are deficient for the NH3 to flow at the minimum flow rate without assistance.
2. Description of the Related Art
It is well known in the art to apply anhydrous ammonia (“NH3”) to the soil to increase its nitrogen content. NH3 application systems typically include a tractor which pulls a tool bar or similar implement or mover for cutting into the soil. Generally, in this arrangement, a small trailer with a storage tank containing NH3 is pulled behind the tool bar. Hosing connections are typically made between the storage tank and the tool bar through which NH3 flows ultimately to knives mounted on the tool bar. The knives are used to inject the NH3 below the surface of the soil.
These known systems and methods take advantage of the fact that NH3 expands nearly 100 times its stored volume when vaporized or in its gaseous state. Thus, if the ambient temperature is sufficiently high to move the temperature of the stored NH3 above its vaporization temperature of −28 degrees F., at least some of the NH3 in the storage tank vaporizes at its vaporization temperature, generating pressure within the tank. This pressure is used to force the vaporized NH3 through the hosing to the knives. After the NH3 is injected into the soil, the NH3 is covered with soil to aid in retention of the injected NH3 by reducing loss of NH3 by evaporation.
Several problems occur with known NH3 application devices. The root of most of these problems is that the systems rely on the ambient temperature being sufficiently high to pressurize the NH3 in the tank to flow out of tank by vaporizing at least some of the stored NH3. In other words, the ambient temperature must be sufficiently high in order to maintain a sufficient amount of the stored NH3 above its vaporization temperature to create sufficient pressure within the storage tank so that the NH3 is urged out of the tank to the knives for injection into the soil. If the ambient temperature is too low, too much of the stored NH3 will be below its vaporization temperature, thus remaining in liquid form, and an insufficient amount of stored NH3 will vaporize. Accordingly, the pressure in the storage tank will be insufficient to force the stored NH3 out of the storage tank, through the hoses to the knives mounted on the tool bar and, ultimately, into the soil.
This problem can result in a simple inability to apply targeted amounts of NH3 in, e.g., fall or winter seasons at economically feasible methods. Alternatively, a small amount of NH3 may be applied if the ambient temperature is at a level where some vaporization of stored NH3 occurs, albeit at an insufficient and/or perhaps variable level wherein the resulting pressure moves between providing sufficient flow rates of NH3 and insufficient, or no, flow rates of NH3. This will obviously result in non-uniform coverage and application of NH3 to the soil.
The art fails to adequately provide a mechanism or method that enables at least a minimum flow of NH3 from the storage tank to the soil, regardless of ambient temperature conditions.
The present invention overcomes these deficiencies.